“Day before yesterday Madame’s maid went to the cashier,” repeated the detective slowly as if rehearsing the case as much for his own information as ours, “and said that Madame had asked her to say to him that she was going away for a few days and that under no circumstances was her room to be disturbed in her absence.  The maid was commissioned to pay the bill, not only for the time they had been here, but also for the remainder of the week, when Madame would most likely return, if not earlier.  The bill was made out and paid.

“Since then only the chambermaid has entered this suite.  The key to that closet over in the corner was gone, and it might have hidden its secret until the end of the week or perhaps a day or two longer, if the chambermaid hadn’t been a bit curious.  She hunted till she found another key that fitted, and opened the closet door, apparently to see what Madame had been so particular to lock up in her absence.  There lay the body of Madame, fully dressed, wedged into the narrow space and huddled up in a corner.  The chambermaid screamed and the secret was out.”

“And Madame de Nevers’s maid?  What has become of her?” asked Kennedy eagerly.

“She has disappeared,” replied McBride.  “From the moment when the bill was paid no one about the hotel has seen her.”

“But you have a pretty good description of her, one that you could send out in order to find her if necessary?”

“Yes, I think I could give a pretty good description.”

Kennedy’s eye encountered the curious gaze of McBride.  “This may prove to be a most unusual case,” he remarked in answer to the implied inquiry of the detective.  “I suppose you have heard of the ‘endormeurs’ of Paris?”

McBride shook his head in the negative.

“It is a French word signifying a person who puts another to sleep, the sleep makers,” explained Kennedy.  “They are the latest scientific school of criminals who use the most potent, quickest-acting stupefying drugs.  Some of their exploits surpass anything hitherto even imagined by the European police.  The American police have been officially warned of the existence of the endormeurs and full descriptions of their methods and photographs of their paraphernalia have been sent over here.

“There is nothing in their repertoire so crude as chloral or knock-out drops.  All the derivatives of opium such as morphine, codeine, heroine, dionine, narceine, and narcotine, to say nothing of bromure d’etyle, bromoform, nitrite d’amyle, and amyline are known to be utilised by the endormeurs to put their victims to sleep, and the skill which they have acquired in the use of these powerful drugs establishes them as one of the most dangerous groups of criminals in existence.  The men are all of superior intelligence and daring; the chief requisite of the women is extreme beauty as well as unscrupulousness.